The specific aims of this study were to investigate the short-term effects of oral losartan on degree and lesion severity of mitral regurgitation (MR) hemodynamic and morphologic abnormalities due to MR and hormonal abnormalities associated with MR. We conclude that treatment of MR using the angiotensin receptor antagonist losartan produces a significant and sustained decrease in the degree of MR, with a decrease in RVol and ERO. However, the changes are of modest and variable magnitude, suggesting that evaluation of long-term effects of potent oral vasodilators on MR in a randomized trial is warranted. This study has resulted in the preparation of one manuscript entitled "Effect of Losartan on Degree of Mitral Regurgitation: A Prospective Open-Label Trial Using Echocardiographic Quantitation".